Abstract. In this work, we studied the electron microscopic features of myocarditis and its possible pathogenetic mechanisms in the long term after the acute stage of COVID-19. The material of the study was pieces of the myocardium of deceased patients diagnosed with post-covid myocarditis. The appearance of viral particles in the interstitial tissue of the myocardium, the development of edema at the submicroscopic level, the destruction of structural elements, the formation of a thrombus in the lumen of the capillary, consisting of platelets, fibrin and plasma protein clots, proves viral myocardial damage in COVID-19. Initially, the interstitial tissue and microvessels of the myocardium are affected, then structural rearrangements of individual cardiomyocytes occur due to viral intoxication, hypoxia and ischemia. The disappearance of the nucleus due to karyolysis, the destruction of myofibrils in the form of homogenization and destruction, the complete destruction of mitochondria and the disappearance of their ultrastructural organization, the increase in the osmophilicity of the matrix due to the accumulation of lipid and calcific inclusions - all this indicates the development of local necrosis of cardiomyocytes in COVID-19.
References:
1. Tavazzi G, Pellegrini C, Maurelli M, Belliato M, Sciutti F, Bottazzi A et al. Myocardial localization of coronavirus in COVID‐19 cardiogenic shock. European Journal of Heart Failure. 2020;22(5):911–5. DOI: 10.1002/ejhf.1828
2. Escher F, Pietsch H, Aleshcheva G, Bock T, Baumeier C, Elsaesser A et al. Detection of viral SARS‐CoV‐2 genomes and histopathological changes in endomyocardial biopsies. ESC Heart Failure. 2020;7(5):2440–7. DOI: 10.1002/ehf2.12805
3. Wenzel P, Kopp S, Göbel S, Jansen T, Geyer M, Hahn F et al. Evidence of SARS-CoV-2 mRNA in endomyocardial biopsies of patients with clinically suspected myocarditis tested negative for COVID-19 in nasopharyngeal swab. Cardiovascular Research. 2020;116(10):1661–3. DOI: 10.1093/cvr/cvaa160
4. Kogan E.A., Berezovskiy Yu.S., Blagova O.V., Kukleva A.D., Bogacheva G.A., Kurilina E.V. et al. Miocarditis in Patients with COVID-19 Confirmed by Immunohistochemical. Kardiologiia. 2020;60(7):4– 10. [Russian: Коган Е.А., Березовский Ю.С., Благова О.В., Куклева А.Д., Богачева Г.А., Курилина Э.В. и др. Миокардит у пациентов с COVID-19, подтвержденный результатами иммуногистохимического исследования. Кардиология. 2020;60(7):4-10]. DOI: 10.18087/cardio.2020.7.n1209
5. Pietsch H, Escher F, Aleshcheva G, Baumeier C, Morawietz L, Elsaesser A et al. Proof of SARS-CoV-2 genomes in endomyocardial biopsy with latency after acute infection. International Journal of Infectious Diseases. 2021; 102:70–2. DOI: 10.1016/j.ijid.2020.10.012
6. Goërtz YMJ, Van Herck M, Delbressine JM, Vaes AW, Meys R, Machado FVC et al. Persistent symptoms 3 months after a SARS-CoV-2 infection: the post-COVID-19 syndrome? ERJ Open Research. 2020;6(4):00542–2020. DOI: 10.1183/23120541.00542-2020 9. Doykov I, Hällqvist J, Gilmour KC, Grandjean L, Mills K, Heywood WE. “The long tail of Covid-19” – The detection of a prolonged inflammatory response after a SARS-CoV-2 infection in asymptoma
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